Press Releases

European Commission Designates MST-188 As An Orphan Medicinal Product

SAN DIEGO, March 25, 2013 /PRNewswire/ -- Mast Therapeutics, Inc. (NYSE MKT: MSTX) today announced that the European Commission (EC) has designated MST-188 as an orphan medicinal product for the treatment of sickle cell disease. This decision follows a positive opinion adopted by the Committee for Orphan Medicinal Products (COMP) recommending such designation.

Brian M. Culley, Chief Executive Officer, said: "Now that we actively are recruiting patients in EPIC, our pivotal phase 3 study of MST-188 in sickle cell disease, we intend to pursue strategic alliances more aggressively. We believe orphan designation and the expectation of 10 years of marketing exclusivity in the EU will enhance partnering interest in Europe. In addition to enabling development in multiple countries and enhancing the overall commercial opportunity for MST-188, partnerships will help fund its development within the U.S."

Mr. Culley continued: "Our recently announced plans to investigate MST-188 in acute limb ischemia, a complication of peripheral arterial disease, also may bolster our partnering efforts. Indeed, we already have been approached by at least one pharmaceutical company that wished to discuss our near- and long-term plans in arterial disease, which we announced just three weeks ago."

About Orphan Medicinal Product Designation

The COMP, one of seven scientific committees of the European Medicines Agency (EMA), is responsible for reviewing applications from companies seeking "orphan medicinal product designation" and making recommendations to the EC regarding these applications. Orphan medicinal product designation is for investigational medicines designed to treat rare diseases that are life-threatening or chronically debilitating and for which there is no satisfactory method of treatment or, if such a method exists, for investigational medicines that may provide significant benefit to those affected by that condition.

Authorized orphan medicines benefit from 10 years of marketing exclusivity in the European Union (EU), meaning that in the 10 years after marketing authorization similar products with a comparable indication cannot be placed on the market, except in limited circumstances. This period of marketing exclusivity is extended by two years for medicines that also have complied with an agreed pediatric investigation plan. The EMA also provides a form of scientific advice specifically for orphan medicines, called protocol assistance. This allows sponsors to receive answers to questions on the types of studies needed to demonstrate the medicine's quality and benefits and risks. In addition, all designated orphan medicines are assessed for marketing authorization centrally in the EU. This allows companies to make a single application to the EMA, resulting in a single opinion and a single decision from the EC, valid in all EU member states.

About Mast Therapeutics

Mast Therapeutics, Inc. is a publicly traded biopharmaceutical company headquartered in San Diego, CA. The Company is leveraging the MAST (Molecular Adhesion and Sealant Technology) platform, derived from over two decades of clinical, nonclinical and manufacturing experience with purified and non-purified poloxamers, to develop MST-188, its lead product candidate, for serious or life-threatening diseases with significant unmet needs. MST-188 is a cytoprotective, hemorheologic, anti-inflammatory and anti-thrombotic agent that has potential utility in diseases or conditions characterized by microcirculatory insufficiency (endothelial dysfunction and/or impaired blood flow).

The Company is recruiting subjects in EPIC, a pivotal phase 3 study of MST-188 in sickle cell disease. The Company plans to initiate a phase 2 clinical study of MST-188 in acute limb ischemia, a complication of peripheral arterial disease, in late 2013 or early 2014. More information can be found on the Company's web site at www.masttherapeutics.com.

Forward Looking Statements

Mast Therapeutics cautions you that statements included in this press release that are not a description of historical facts are forward-looking statements that are based on the Company's current expectations and assumptions. Such forward-looking statements include, but are not limited to, statements regarding prospects for success of MST-188 development programs in and outside of the U.S., the Company's focus on and the potential for strategic alliances involving MST-188, the positive effects that the EMA's orphan designation may have on MST-188's regulatory, commercial and partnering prospects, including the potential for 10-year marketing exclusivity and for increasing partnering interest in the EU, and the potential benefits of partnering MST-188, including enabling its development in multiple countries, enhancing the overall commercial opportunity for MST-188 and funding its development within the U.S. Among the factors that could cause or contribute to material differences between the Company's actual results and expectations indicated by the forward-looking statements are risks and uncertainties that include, but are not limited to: the risk that, upon re-evaluation at the time of application to the EMA for marketing authorization, the COMP or the EC may determine that MST-188 for the treatment of sickle cell disease no longer meets the criteria for orphan designation, meaning that MST-188 would not benefit from the 10-year marketing exclusivity for authorized orphan medicines; the potential that partnering transactions involving MST-188 may not advance its development in other jurisdictions, enhance the overall commercial opportunity of the product candidate or help fund its development within the U.S.; the potential for significant delays in the development of MST-188, including as a result of delays in the commencement or completion of clinical studies, including due to difficulties in obtaining regulatory agency agreement on clinical development plans or clinical study design, opening trial sites, enrolling study subjects, manufacturing sufficient quantities of clinical trial material, completing necessary manufacturing process development activities, and being subject to a "clinical hold," or suspension or termination of a clinical study, including due to lack of adequate funding or patient safety concerns; the potential for institutional review boards or the FDA, the EMA or other regulatory agencies to require additional nonclinical or clinical studies prior to initiation of planned phase 2 clinical studies of MST-188 in any particular indication in which the Company determines to develop MST-188, including acute limb ischemia, which likely would increase the total time and cost of development in the indication; the risk that clinical studies of MST-188 are not successfully executed and/or do not successfully demonstrate its safety or efficacy; the risk that, even if clinical studies are successful, the FDA, the EMA or other regulatory agencies may determine they are not sufficient to support a new drug application; the risk that even if clinical studies of MST-188 in one indication are successful, clinical studies in another indication may not be successful; the potential for unsuccessful nonclinical or clinical studies in one indication or by a future partner that may be outside of the Company's control to adversely affect opportunities for MST-188 in other indications or jurisdictions; the Company's reliance on contract research organizations (CROs), contract manufacturing organizations (CMOs), and other third parties to assist in the conduct of important aspects of MST-188's development, including clinical studies and regulatory activities, and that such third parties may fail to perform as expected; the Company's ability to obtain additional funding on a timely basis or on acceptable terms, or at all; the potential for the Company to delay, reduce or discontinue current and/or planned development activities, including clinical studies, partner MST-188 at inopportune times or pursue less expensive but higher-risk and/or lower-return development paths if it is unable to raise sufficient additional capital as needed; the risk that acceptable partnering opportunities for MST-188 may not be available in particular jurisdictions or indications and, consequently, the Company may not be able to pursue development of MST-188 in certain jurisdictions and indications; the risk that the FDA, the EMA or other regulatory agencies do not grant marketing approval of MST-188, on a timely basis, or at all; the risk that the Company is not able to adequately protect its intellectual property rights relating to the MAST platform and MST‑188 and prevent competitors from duplicating or developing equivalent versions of MST-188; and other risks and uncertainties more fully described in the Company's press releases and periodic filings with the U.S. Securities and Exchange Commission. The Company's public filings with the U.S. Securities and Exchange Commission are available at www.sec.gov.

You are cautioned not to place undue reliance on forward-looking statements, which speak only as of the date when made. the Company does not intend to revise or update any forward-looking statement set forth in this press release to reflect events or circumstances arising after the date hereof, except as may be required by law.

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